Purpose: :
In a recent study, a carbohydrate–binding protein,E–selectin (ELAM–1), was identified as a specificmolecular marker of glaucoma. Selectins are a family of transmembrane,carbohydrate–binding proteins characterized by their affinityfor sialated and sulfated Lewisx (Lex) and Lewisa (Lea) oligosaccharides.In our attempt to understand the role of carbohydrate–basedrecognition systems in the pathogenesis of glaucoma, the goalof the present study was to determine which specific membersof the selectin family and/or their counterreceptors are differentiallyexpressed in trabecular meshwork (TM) and aqueous humor of patientswith POAG.

Methods: :
TaqMan Q–PCR was used to determine which specificmembers of the selectin family are differentially expressedin whole glaucomatous and normal TM tissue. Slotblot analysiswas performed to determine whether selectins and their counter–receptors,specifically sialyl–Lex , are differentially expressedin the aqueous humor of normal subjects and of patients withPOAG.

Results: :
Q–PCR analysis revealed that the expression ofE–selectin as well as that of another member of the selectinfamily, P–selectin, is markedly upregulated in TMs ofdonors with POAG (Normal:POAG, E–selectin 1:10.3; P–selectin1:12.7, triplicate samples from three normal and two glaucomaspecimens were analyzed). Slot blot analysis revealed that E–selectinas well as its counterreceptor, sialyl–Lex, were alsopresent in significantly higher amounts in aqueous humor ofpatients with POAG compared to the aqueous humor collected fromcataract patients (Sialyl Lex [ng/µl]: Glaucoma, 24.42± 4.34, Control: 9.93 ± 3.29; E–selectin:POAG [ng/µl]: 110.85± 21.33, Control, 51.36 ng± 7.58; triplicate samples from two each of control andPOAG samples were analyzed). Analysis of additional aqueoussamples as well as P–selectin and sialyl–Lea iscurrently underway.

Conclusions: :
These data support the hypothesis that one or moreselectin–mediated, carbohydrate–based recognitionsystems have the potential to play a role in the pathogenesisof glaucoma.